Vegetable Glycerin extract or VG cannabis have been my key words for google searches; I've found a couple methods (I'm impatient, so really only found one - the second one takes 3-6 months).
Full disclosure VG extraction will not be as potent as other extractions according to all the internet experts... science; I'll have to trust that, but this method still gets me high as fuck, so I really don't care (maybe I need to vape a little more than if using PEG, but this is super cheap and ... well, to repeat, it gets me high as fuck so I don't give a shit).
Ruff House studios have a video and marijuanabreak.com has good article. They use a double boiler with oil to reach stable temps; I have a convection oven that can hold low temps fairly well. My 'reminder' guide below using convection oven:
I weigh and measure everything because I'm kind of looking for consistency... but weed strains vary, so grain of salt here...
use two 'tall' shot glasses; 1 for infusion; 1 for filtering/decarbing
---> shot glass #1
. 2g bud (use grinder)
. 6-8 mil vape juice; just cover; start with 8 and use 1 less each time; used 8, 7, 6 recovered 15
. cover wth aluminum foil whenever putting in oven (if not covered, sometimes i get a burnt taste/smell to juice)
. heat conv. to 180 for 45-60 mins (infuses vg/pg) - set 10-15 minute timers; stirring each time
. use strainer; smash with spoon or spatula (careful not to break spatula or strainer)
. drip thru strainer into bowl (or straight into coffee-filtered shot glass #2 if possible)
. REPEAT THREE TIMES
---> shot glass #2
. strain thru coffee filter into shot glass - squeeze as needed
. cover wth aluminum foil
. heat to 220 for 30-35 mins (decarboxilates)
I buy 70/30 VG/PG 0mg nicotine vape juice from vapes.com. They sell 100ml bottles for $10 and charge $5.95 shipping... I buy 3 or 4 at a time to make it cheaper.
If you know of, or can find a quicker, cheaper and easier way to make THC vape juice, I'm all ears...
My motivation for making vape juice is; I have unsmokable buds and I would rather find a new way to use than toss out - and I don't want to spend any money on more supplies or recovery systems or purging devices or use a product that has some negative potential. I want it to be quick, cheap and easy... and taste good